The overall objective of the proposed research is to provide a better understanding of the neural process underlying the sensation of vision. In particular, the project has as its goal an evaluation of the contribution of specific groups of neurons in visual cortex to specific spatial vision capacities. The basic strategem is to compare human and animal psychophysical measures with electrophysical measures to identify possible isomorphic relationships, and to note the psychophysical changes after manipulation of the neural populations in animals. These procedures will confirm or falsify hypotheses regarding the role of specific neuron sets in vision and thus further and understanding of the neural substrates of vision. Cats will be employed as the animal model both because of the large amount of data available about its visual system and the fortuitous apparent segregation of portions of its visual system that make it possible to examine the role of separate cell populations. Experiments are proposed which will: (1) attempt to further evaluate the cortical mechanisms involved in spatial contour vision; (2) evaluate the role of specific cortical areas in accommodation; (3) characterize the visual deficits in animals with abnormally developed visual system; (4) further develop visual tests that might be useful in diagnosing specific deficits in spatial vision.